钙芒硝水力压裂下裂缝扩展规律及影响因素研究  

Study on Fracture Propagation Law and Influencing Factors under Glauberite Hydraulic Fracturing

作　　者：刘晨[1] 徐素国[1] Liu Chen;Xu Suguo(Key Laboratory of In-situ Property Improving Mining of Ministry of Education,Taiyuan University of Technology Taiyuan 030000,P.R.China)

机构地区：[1]太原理工大学原位改性采矿教育部重点实验室,太原030000

出　　处：《地下空间与工程学报》2023年第5期1536-1543,1632,共9页Chinese Journal of Underground Space and Engineering

基　　金：国家杰出青年基金资助项目(50804033)。

摘　　要：为实现钙芒硝原位改性流体化开采,采用了实验室真三轴压裂模拟装置,探究在不同地应力、不同水温条件下钙芒硝水力压裂裂缝扩展规律,同时利用模拟软件探究地应力差和多井压裂对水力压裂裂缝扩展的影响。结果发现:在低应力差条件下,裂缝在压裂井附近可以形成较复杂的裂缝网络,高应力差下裂缝则扩展的更远,但裂缝形态较为单一;对比不同水温下钙芒硝水力压裂曲线发现,温度越高,钙芒硝的起裂压力越小,裂缝扩展阶段压力波动现象更为明显,该现象与钙芒硝裂缝边界溶解有关;通过数值模拟发现当进行多井压裂时,水力压裂裂缝的扩展易受局部应力的改变而被抑制或者偏转。研究成果可对钙芒硝流体化开采提供实际工程指导。In order to explore the hydraulic fracturing and fracture propagation law of glauberite,the true triaxial fracturing simulation device in the laboratory is used to explore the fracture propagation law of glauberite hydraulic fracturing under different in-situ stress and different water temperature.At the same time,the simulation software is used to analyze the influence of in-situ stress difference and multi well fracturing on hydraulic fracturing fracture propagation.The results show that:Under the condition of low stress difference,the fracture can form a more complex fracture network near the fractured well,while under the condition of high stress difference,the fracture will expand further,but the fracture geometry is relatively single.Comparing the hydraulic fracturing curves of glauberite under different water temperatures,it is found that with the higher temperature,the crack initiation pressure of glauberite is smaller,and the pressure fluctuation in the crack propagation stage is more obvious.The analysis is related to the dissolution of glauberite fracture boundary.Through numerical simulation,it is found that during multi well fracturing,the hydraulic fracturing fracture is easy to deflect due to the change of local stress.The research results can provide practical engineering guiding for the fluid mining of glauberite.

关 键 词：水力压裂 钙芒硝 裂缝扩展 裂缝形态 

分 类 号：TD871[矿业工程—非金属矿开采]